The South Mountain State Battlefield encompasses Crampton's, Fox's, and Turner's Gaps of South Mountain. Its diverse terrain features rolling farmland of western Maryland and the deep forests of the Appalachian Trail. The first battle of the Maryland Campaign of 1862 was fought in these mountain gaps on September 14, 1862. Begin with a visit to the office and museum at Washington Monument State Park just north of Alternate U. S. Route 40. The Old South Mountain Inn on Route 40, known in 1862 as the Mountain House, served as D. H. Hill’s headquarters during the battle.